... , blue, green, yellow, amber, pink, purple lab use Ground glass joints of borosilicate 3.3 pyrex are used in laboratories to ... -tight apparatus together from commonly available parts. For example, a , , and with ground glass joints may be rapidly fitted together to a ... the inside and open at the ends, except for stoppers.Glass ground joints of borosilicate 3.3 pyrex types:Conically tapered jointsBall ...